The coal mining industry in and around Wollongong, New South Wales, Australia, is responsible for producing an ever growing quantity of coal washery reject materials and other mine waste aggregates. Considerable effort is being undertaken to reuse, beneficially, these waste products in the immediate suburbs of Wollongong. In this paper, detailed laboratory investigations carried out on coal wash (i.e. coarse coal washery reject), produced at Dendrobium coal mine near Wollongong, are presented. Geotechnical tests were conducted to determine the particle size distribution, compaction characteristics, shear resistance and collapse potential. Compaction tests were performed under dry and submerged conditions to examine comprehensively the compactability and the strength properties of coal wash. The laboratory tests show that, if properly compacted, Dendrobium coal wash has a good potential as effective low-porosity fill for embankments and port reclamation. Keywords: coal wash; collapse potential; compaction; shear strength; structural fill